1. Field of the Invention
The present invention concerns a radar system, notably for the correction of artillery fire.
2. Description of the Prior Art
The correction of the firing of shells (or rockets) requires a preliminary appreciation of the error between the objective that is aimed at and the explosion of the shell. The usual method used to determine the angle error, between the objective that is aimed at and the explosion of the shell, is an angle error measurement method based on the use of a radar of the "monopulse" type, i.e. a radar where the antenna has two distinct and complementary patterns: one sum pattern .SIGMA., which is the usual pattern, i.e. with a maximum gain in the axis of the antenna, and a difference pattern .DELTA. having, on the contrary, a null gain along this very same axis and for which the phase with reference to E changes sign on either side of this axis. The ratio .DELTA./.SIGMA. between the amplitudes of the signals reflected by a determined target, respectively obtained at the corresponding .DELTA. and .SIGMA. channels, represents, to a certain extent, the angle error between this target and the axis of the antenna.
While this method of error measurement gives good results when applied to the tracking of a target, it has a major drawback in the measurement of errors between the explosion of the shell and the objective aimed at. This drawback is that the ratio .DELTA./.SIGMA. represents the angle error only in a limited zone of the pattern .DELTA. where this pattern is linear.